Tapping Weaker Waves to Power the Future

Most researchers wear lab coats or business attire to work. Mike Raftery wears a wet suit.

That’s because Raftery spends his days working in and around a wave tank at Stevens Institute of Technology, in Hoboken. He’s often in the water to test the capability of a float to generate power from waves created in the lab, as he looks to manipulate ocean wave strength to make wave power a more viable option.

“We have a great wave energy resource off the East Coast,” said Raftery, president and CEO of Seahorse Power LLC. “If we can develop a device like this to tune waves and concentrate wave power … we can provide a long-term, stable power supply from wave energy to the people of the United States.”

The device’s efficiency is measured by a floating red, foam ball bobbing roughly in the middle of the tank. When the waves reach about three inches in height, they cause the float to gently bob. After Raftery attaches the float to a submerged platform that heightens those same waves, the foam ball moves much faster — and the faster the float moves, the more electricity it’s capable of generating.

New Jersey’s mild waves are typically less than two feet high, he said, but using the platform, he can tune that wave to over three feet.

“On the average day, for every meter of wave crest that we’re pulling energy out of we can power 14 homes,” he said. “This is a very scalable design. We can take 10 meter-wide buoys with the average waves and power 140 homes with that.”

The plan isn’t to just have 10 floats in the water. Instead, Raftery wants to place at least 10 buoys in one area, which would then power 1,400 homes — essentially, the output of a wind turbine.

“So we’re looking at producing the same kind of power per footprint on the ocean as a wind turbine,” Raftery said.

These projections aren’t possible without tuning the waves, which is a new concept. First-generation wave energy devices have proven New Jersey’s waters aren’t strong enough otherwise, said Robert Lurie, vice president of North America business development and marketing for Ocean Power Technologies, though the company has been testing off the Garden State’s coast since 1997. OPT’s wave energy converter simply works with the waves as they are, and doesn’t attempt to steepen them.

OPT’s technology “works best in places that have fairly strong waves and fairly consistent waves throughout the year,” he said. In the United States, that means the West Coast from about San Francisco to Alaska, and Hawaii. Other countries in the world where OPT’s design works well are Japan, Australia and those in northern Europe.

Even with completely calm seas, Raftery said, his design can work because it stores energy. For an hour without any waves, the float can still power 300 homes.

The next step is to win interest from investors, Raftery said. Right now, he is working with the Office of Naval Research to test the design, aiming to prove the platforms will pay out 12 cents a kilowatt hour. Translating that to a megawatt barge would mean $1 million a year per platform in electricity revenue.

“Energy is one of the ultimate commodities because it sells in 15-minute blocks, and if you have a carbon-free energy, then you have a good leverage for selling your resources at a premium,” he said.

At the prices he’s hoping to get, Raftery believes he can make a good business case for putting 1,000 buoys in the water, but the program has been in testing for six years while he tries different scale models and works to make the model more resilient.

At the end of March, the model will be tested in a wave tank double the size of Stevens’, at the National Oil Spill Response Test Facility in the Leonardo section of Middletown. Raftery believes that if he can get his model to work there, and prove the model can withstand stronger waves, then the state of New Jersey might be willing to get involved, especially because of the renewable-energy requirements in its energy master plan.

Raftery envisions energy islands off the coast of New Jersey that sport wind turbines, surrounded by wave-energy converters, and covered in solar panels. After all, if sections of the ocean are going to be leased for energy conversion, Raftery doesn’t see why New Jersey shouldn’t try to wring as much energy as possible out of the area.

“The 2020 timeline is coming quickly, and we’re hoping that ups the urgency of people looking at waves as a real viable source to meet that metric for New Jersey,” Raftery said.